The present invention relates to a holographic display and, more specifically, to a holographic display module incorporated into a machine which provides a visual, three-dimensional display alerting and prompting a user of machine status and/or malfunctions.
Visual display panels for communicating the status of a machine to an operator are well known in the art. Displays are used, for example, to provide alphanumeric information relating to conditions in a document reproduction machine; e.g. "COPY SELECT", "STANDBY", "READY", and the like. Graphic displays which illustrate a machine configuration in conjunction with "mimic" components are also known. As one example, U.S. Pat. No. 4,475,806, assigned to the same assignee as the present invention, discloses a liquid crystal display wherein selectively energizable liquid crystal elements corresponding to copier components are rendered visible under the control of a microprocessor. An overlay pattern is placed above the liquid crystal display to present to the user in outline form the copier architecture with which he is interacting. Graphic types of panel displays have been incorporated into commercial machines such as the Xerox 1090 and Xerox 1065 copiers.
These prior art device display panels present two-dimensional configurations and are thus limited in providing information relating to internal areas of a machine. Moreover, with these prior art displays, a user must therefore be in a precisely defined visual orientation with the display to obtain an undistorted view. A panel providing three-dimensional information would overcome these prior art disadvantages. Holographic displays, used in "head's-up" displays for aircraft are known in the art as exemplified by the disclosure in U.S. Pat. No. 3,915,548. As described in this patent, a holographic array functions as both a collimating lens and a combiner for a light image from a liquid crystal source. In U.S. Pat. No. 4,372,639 a holographic element diffuser is combined with a liquid crystal panel to provide a display panel with improved brightness and viewability. A hologram has been combined with an electronically driven two layered crystal diode array in a game configuration as disclosed in an article entitled "Mass produced holograms forthe entertainment industry" by Stephen P. McGrew, published January 1983 in the Proceedings of SPIE, Volume 391, pages 19 and 20. These prior art holographic displays incorporate designs and functions which are not suitable or transferable to the different requirements of a graphic-type display to represent machine components and functions. With particular reference to the aforementioned document, reproduction machine factors such as space limitations, manufacturing assembly procedures, focusing requirements, costs, etc. have hitherto proved to be an impediment to incorporating a holographic display in a xerographic copier. The present invention is therefore directed, in a first embodiment, to a display module which utilizes an addressable liquid crystal panel in conjunction with a nonlens holographic plate without focal power having formed thereon a three-dimensional image of the particular machine. The display module incorporates an illumination system which optimizes illumination of the holographic plate. In a second embodiment, a plurality of separate light sources are located in a substrate adjacent the holographic plate. The light source is selectively energized to illuminate the selected locations of the machine. More particularly, the invention relates to a machine having a plurality of operating subsystems, a holographic display system for providing to an operator of said machine a holographic visual display relating to the status of various machine operations, said display system comprising, in combination:
a holographic display element having formed thereon a holographic representation of a machine outline,
illumination means for providing illumination to selected areas of said display element, and
control circuitry for detecting a particular machine operation status, and for energizing said illumination means so as to illuminate said holographic display element.